Vitamin D doesn't cut prostate cancer risk

WASHINGTON (Reuters) - Vitamin D -- the so-called sunshine vitamin -- does not appear to cut a man's risk of getting prostate cancer, researchers said on Tuesday.

Previous studies have found protective effects from higher vitamin D levels for certain cancer types including colon and breast cancer, as well as other ailments.

U.S. National Cancer Institute researchers set out to see if vitamin D might protect against prostate cancer, the second most frequently diagnosed cancer in men worldwide. They tracked vitamin D concentrations in the blood of 749 men diagnosed with prostate cancer and 781 men who did not have the disease.

They found no association between higher levels of the vitamin and a reduced prostate cancer risk. The findings hinted at a possible increased risk for aggressive prostate cancer in men with higher blood concentration of vitamin D, but this link was not statistically significant, the researchers said.

"In our study, we didn't see any protective effect of vitamin D in relation to prostate cancer risk," Jiyoung Ahn of the U.S. National Cancer Institute, one of the researchers, said in a telephone interview.

Levels of vitamin D were measured in a blood sample provided by the men when they entered the study. Those with prostate cancer were diagnosed one to eight years after the blood samples were given, the researchers said.

Ahn, whose study was published in the Journal of the National Cancer Institute, said previous research had shown that high doses of vitamin D inhibited the growth of human prostate cancer cells in a laboratory dish.

The body makes vitamin D when skin is exposed to sunlight, thus earning its nickname the sunshine vitamin. It is found in fatty fish such as salmon and milk commonly is fortified with it.

Vitamin D helps the body absorb calcium and is considered important for bone health. In adults, vitamin D deficiency can lead to osteoporosis, and it can lead to rickets in children.

Some studies have indicated it might provide other benefits. For example, one study published in January found that people with low vitamin D levels had an elevated risk for heart attack, heart failure and stroke, suggesting it may protect against cardiovascular disease.

National Cancer Institute researchers found in a study published last October that people with higher vitamin D levels were less likely to die of colorectal cancer but it did not appear to affect the risk of dying from other cancer types.

But Canadian researchers reported earlier this month that women with breast cancer who had lower levels of vitamin D were more likely to die and more likely to have their cancer spread than women with normal levels of the vitamin.

The American Cancer Society estimates that about 780,000 men are diagnosed annually with prostate cancer worldwide, with about 250,000 deaths a year. The group called prostate cancer the sixth leading cause of cancer death in men worldwide.

(Editing by Maggie Fox and Bill Trott)